of course we don't deploy a network accounting for every machine at 200mb/s flat 24/24, this would just be throwing money away. The reality is that most users won't be using these 200mb/s constantly, every customer have different traffic pattern usages.
We (online.net) have a long history in dedicated servers (yes we have a >1tb/s global network footprint), we known how to scale the network the proper way. It is carefully monitored, when upgrades are needed, we do upgrade (for example you can check on status.online.net network section, you will see that we upgrade when it is needed, we have quite a few ongoing)
the same applies to scaleway, we can upgrade network uplinks if needed and we do monitor that closely
Note that only uplinks to the backbone are "shared", each 1gb/s port of the servers really are dedicated
Hope this clarifies the design :)
Do you mean the 1Gbps port for the enclosure (i.e. the server hosting the 912 blades)? If so, unless you're providing many 1Gbps links you're not anywhere close to providing good quality networking for these